JP3987278B2 - Method for converting 1,4-butynediol to 1,4-butenediol - Google Patents

Abstract

A process for the preparation of 1,4 butenediol comprising hydrogenating an aqueous solution of 1,4 butynediol under stirring conditions over a supported platinum or palladium and nickel catalyst in basic medium at a temperature in the range of 20 - 110 DEG C and pressure in the range between 200 - 700 psig till the reaction is completed, cooling the reaction mixture to room temperature and separating the catalyst by known methods to obtain 1, 4 butenediol.

Description

[0001]
The present invention relates to a process for the conversion of 1,4-butynediol to 1,4-butenediol by selective liquid phase hydrogenation. More particularly, the present invention relates to a process for the conversion of 1,4-butynediol to 1,4-butenediol in a basic medium using a novel noble metal-containing catalyst.
[0002]
Background of the Invention
Butenediol is a useful intermediate agrochemicals, in pesticides and production of vitamin B _6. Because it is an unsaturated diol, it can be used in the synthesis of many organic products such as tetrahydrofuran, n-methylpyrrolidione, γ-butyrolactone, and the like. It is also used as an additive in the paper industry, as a stabilizer in resin production, as a lubricant for bearing systems, and in the synthesis of allyl phosphate.
[0003]
The prior art discloses the use of many catalysts for the production of 1,4-butenediol by hydrogenation of 1,4-butynediol. Most prior art patents are based on a combination of palladium and one or more mixed compounds such as copper, zinc, calcium, cadmium, lead, alumina, mercury, tellurium, gallium and the like. GB A 871804 describes the selective hydrogenation of acetylenic compounds in a suspension process using a Pd catalyst treated with a salt solution of Zn, Cd, Hg, Ga, Th, In or Ga. This process is carried out under mild conditions, with a selectivity to cis 1,2-butenediol of 97% and a selectivity to the trans form of 3%. Furthermore, the use of organic amines as promoters in catalyst systems has been proposed.
[0004]
US Pat. No. 2,681,938 discloses the use of Lindlar catalyst (lead-doped Pd catalyst) for the selective hydrogenation of acetylenic compounds. The disadvantage of this method is the use of an additional amine such as pyridine so that the selectivity for 1,4-butenediol is good.
[0005]
German patent DE 1,213,839 describes a Pd catalyst doped with Zn salt and ammonia for the partial hydrogenation of acetylenic compounds. However, this catalyst has the disadvantage of a short life due to poisoning.
[0006]
German patent specification DE A 2,619,660 describes the use of a Pd / Al ₂ O ₃ catalyst treated with carbon monoxide for the hydrogenation of butynediol in an inert solvent. The disadvantage of this catalyst is that it is treated with carbon monoxide gas which is very toxic and difficult to handle.
[0007]
U.S. Pat. No. 2,961,471 discloses a Raney nickel catalyst useful for the partial hydrogenation of 1,4-butynediol. The catalyst of this process gives a low selectivity to 1,4-butenediol. Other U.S. Pat.No. 2,953,604 discloses Pd-containing charcoal and copper catalysts for the reduction of 1,4-butynediol to 1,4-butenediol. The selectivity to butenediol is 81%. However, this method produces a large number of by-products and is therefore undesirable.
[0008]
U.S. Pat. No. 4,001,344 describes the production of 1,4-butenediol by selective hydrogenation of 1,4-butynediol, at 65 ° C. to 72 ° C. and at a hydrogen pressure of 4 to 12.5 bar. The use of palladium mixed with γ-Al ₂ O ₃ with both zinc and cadmium, or either zinc or cadmium and bismuth or tellurium. However, a variety of residues are formed (7.5-12%), reducing the selectivity to 1,4-butenediol to 88%.
[0009]
US Pat. Nos. 5,521,139 and 5,728,900 describe the use of Pd-containing catalysts for the hydrogenation of 1,4-butynediol to produce 1,4-butenediol. The catalyst used is a fixed bed catalyst prepared by sequentially applying Pd and Pb or Pd and Cd by vapor deposition or sputtering to a metal gauze or metal foil acting as a support. Also, in this method, the selectivity obtained for cis 1,4-butenediol is 98%. The disadvantage of this method is that transbutenediol is obtained with the residue.
[0010]
All of the above catalysts for the hydrogenation of butynediol to butenediol have drawbacks such as containing more than two metals with other promoters such as organic amines. Their production is cumbersome and all reported catalysts do not give full selectivity to the desired product, 1,4-butenediol. The formation of by-products and residues that affect the efficiency of the process has also been reported and the recovery of pure 1,4-butenediol is difficult. Another drawback of prior art catalysts is short life due to rapid deactivation.
[0011]
The prior art literature shows that the catalysts used for the hydrogenation of 1,4-butynediol are mainly catalysts based on palladium or nickel. There is no disclosure or report of a platinum-based catalyst or a catalyst containing a combination of palladium and nickel for the hydrogenation of 1,4-butynediol to produce 1,4-butenediol.
[0012]
It is therefore important to obtain and / or develop a catalyst that overcomes the shortcomings of the above prior art catalysts used in the hydrogenation of 1,4-butynediol to 1,4-butenediol.
[0013]
Objects of the present invention The main object of the present invention is to provide an inexpensive and efficient method for producing 1,4-butenediol by hydrogenation of 1,4-butynediol.
Another object of the present invention is to provide a process for producing 1,4-butenediol with 100% selectivity.
Another object of the present invention is the use of 1,4-butynediol 1,4 with a noble metal catalyst, optionally containing nickel, on a suitable support under mild conditions without poisoning. -To provide a method for conversion to butenediol.
A further object of the present invention is to provide a process for the conversion of 1,4-butynediol to 1,4-butenediol that exhibits 100% selectivity to the production of cis 1,4-butenediol.
A further object of the present invention is to provide a process for the conversion of 1,4-butynediol to 1,4-butenediol using a stable catalyst that can be recycled many times without losing activity and selectivity. It is to be.
Another object of the present invention is to provide a process for the production of 1,4-butenediol with 100% selectivity for the production of cis 1,4-butenediol by mere separation of the catalyst.
[0014]
SUMMARY OF THE INVENTION Accordingly, the present invention provides an aqueous solution of 1,4-butynediol under agitation conditions on a supported platinum, palladium and nickel catalyst in a basic medium at a temperature in the range of 20-110 ° C. And hydrogenating until the reaction is complete at a H ₂ pressure in the range of 200-700 psig, cooling the reaction mixture to room temperature, and separating the catalyst by known methods to obtain 1,4-butenediol. The production of 1,4-butenediol.
[0015]
In one embodiment of the invention, the concentration of 1,4-butynediol in the aqueous medium ranges from 10-50%.
[0016]
In another embodiment of the invention, the pH of the reaction mixture is maintained in the range of 8-10 by adding a base such as ammonia.
[0017]
In a further aspect of the invention, the temperature of the reaction is preferably in the range of 30-90 ° C.
[0018]
In yet another embodiment of the invention, the catalyst is recycled 10 times without losing its activity or selectivity, and the turn over number (TON) is 4 × 10 ³ h ⁻¹ .
[0019]
In yet another embodiment of the invention, the catalyst is of the general formula AB (y) C (z), wherein A is a support comprising calcium carbonate or zeolite, B is platinum or palladium, and y is 0 .2-10%, C is nickel, and z is 0-15.0%, provided that z is 0 when B is Pt.
[0020]
DETAILED DESCRIPTION OF THE INVENTION The present invention, the catalyst is in agitated basic medium (pH = 7 to 12) in water, a carrier _{(e.g., CaCO 3, MgCO 3, BaCO} 3 or NH ₄ -ZSM5) palladium Alternatively, it is prepared by impregnation with a platinum catalyst precursor and heated at a temperature in the range of 60-120 ° C, preferably 70-90 ° C. The mixture is then reduced by adding a conventional reducing agent such as formaldehyde. The solution is stirred, filtered, washed and dried in still air at a temperature in the range of 100-250 ° C, preferably 140-200 ° C, for 5-12 hours.
[0021]
The hydrogenation catalyst used in the process of the present invention has a general formula of AB (y) C (z) (wherein A is a support containing a salt or zeolite of a Group IIA metal, B is a noble metal, y is 0.2 to 10%, C is nickel, and z is 0 to 15.0%, provided that z is 0 when B is Pt).
[0022]
General Formula AB (y) C (z) (wherein A is a carrier comprising a Group IIA metal salt or zeolite, B is Pd or Pt, y is 0.2-10%, C Is a nickel and z is between 0 and 15.0%, provided that when B is Pt, z is 0).
i. Pd or Pt precursor is dissolved in mineral acid by stirring at a temperature in the range of 60-120 ° C.
ii. Dilute the solution by adding water.
iii. Adjust the pH of the solution to a range of 8-12 by adding a base.
iv. Add carrier to the above solution.
v. Heat the mixture to a temperature in the range of 60-120 ° C.
vi. The above mixture is reduced using a conventional reducing agent.
vii. The formed catalyst is separated by any conventional method.
viii. The product is washed and dried to obtain the catalyst.
[0023]
The catalyst can optionally have a combination of Pd and nickel. When the noble metal contains palladium and z is 0.2-15%, the catalyst obtained at the end of step viii. Above is treated with a solution of nickel in a basic medium having a pH in the range of 8-12. Mix, stir the mixture for about 1 hour, and separate the catalyst by any conventional method. The catalyst was then dried in static air for a period of 10 hours or less at a temperature of about 150 ° C. and reduced under a flow of hydrogen at a temperature in the range of 390 to 420 ° C. for 5 to 12 hours. The catalyst is separated by any conventional method and washed and dried to obtain the final catalyst containing palladium and nickel.
[0024]
The source of Pd or Pt is a salt of Pd or Pt selected from the group consisting of acetate, bromide and chloride, and the source of nickel is selected from the group consisting of acetate, carbonate, chloride and nitrate Nickel salt.
[0025]
The support is a Group IIA metal salt selected from the group consisting of magnesium, calcium and barium acetates, nitrates, chlorides and carbonates, and the source of the zeolite is NH ₄ -ZSM5.
[0026]
The base used can be selected from the group consisting of sodium carbonate, potassium carbonate, potassium hydroxide and sodium hydroxide.
[0027]
The reducing agent used in the production of the catalyst is selected from the group consisting of hydrazine hydrate, hydrogen-containing gas and formaldehyde.
[0028]
The catalyst produced according to the following procedure in the examples can be reduced in a muffle furnace at 400 ° C. under a stream of hydrogen for 5 to 12 hours, preferably 7 hours.
[0029]
In a feature of the invention, high purity 1,4-butenediol can be easily obtained by removal of the catalyst from the product stream. Under relatively mild process conditions, the selectivity of the process is 100%.
[0030]
The present invention achieves 100% conversion of 1,4-butynediol with 100% selectivity to cis 1,4-butenediol under mild process conditions. At higher temperatures, 1,4-butynediol is fully converted, but the selectivity to cis 1,4-butenediol is lower, generally below 90%. At higher temperatures, the formation of by-products such as acetal, γ-hydroxybutalaldehyde, butanol becomes more pronounced.
[0031]
The hydrogenation of 1,4-butynediol involves the presence of a Pd or Pt containing catalyst suspended in a mixture of 1,4-butynediol in water in an autoclave at the temperature and pressure conditions as described in the examples. Below, it is carried out under stirring conditions. The mixture is made alkaline (pH = 8-12) by the addition of a base such as ammonia. Before pressurizing the autoclave, make sure there is no air in the autoclave. Hydrogenation is complete when hydrogen absorption stops or does not change. After the reaction is complete, the reactor is cooled to ambient temperature and the contents are removed and analyzed using gas chromatography.
[0032]
The invention is illustrated by the following examples. However, the following examples are illustrative and should not be construed as limiting the scope of the invention.
[0033]
Example 1
Production of Pd-supported catalyst Impregnated with a palladium precursor such as palladium chloride PdCl _{2 on} a support (eg CaCO ₃ , MgCO ₃ , BaCO ₃ or NH ₄ -ZSM5) in a basic medium stirred in water The catalyst is prepared by heating and heated at 80 ° C. The mixture is then reduced by adding formaldehyde. The solution is stirred, filtered, washed and dried at 150 ° C. for 10 hours.
[0034]
Example 2
Preparation of Pt-supported catalyst Impregnation of a support (eg CaCO ₃ , MgCO ₃ , BaCO ₃ or NH ₄ -ZSM5) with a platinum precursor such as platinum chloride in a basic medium stirred in water. The catalyst is prepared by heating and heated at 80 ° C. The mixture is then reduced by adding formaldehyde. The solution is stirred, filtered, washed and dried at 150 ° C. for 10 hours.
[0035]
Example 3
Performance of 1% Pd / MgCO ₃ catalyst in the hydrogenation of 1,4-butynediol to 1,4-butenediol This example illustrates 1 in the hydrogenation of 1,4-butynediol to 1,4-butenediol Illustrates the performance of% Pd / MgCO ₃ catalyst.
The catalyst is prepared by impregnating MgCO ₃ support with the palladium precursor PdCl ₂ in a basic medium stirred in water and heated at 80 ° C. The mixture is then reduced by adding formaldehyde. The solution is stirred, filtered, washed and dried at 150 ° C. for 10 hours.
The reaction in the presence of this catalyst was carried out in an autoclave according to the procedure described above.
The reaction was carried out under the following reaction conditions.
Concentration of 1,4-butynediol in water: 20%
Catalyst weight: 0.13 g
Temperature: 50 ° C
H ₂ pressure: 350 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 99.8%
[0036]
Example 4
Performance of 1% Pd / CaCO ₃ catalyst in the hydrogenation of 1,4-butynediol to 1,4-butenediol This example illustrates 1 in the hydrogenation of 1,4-butynediol to 1,4-butenediol The performance of% Pd / CaCO ₃ catalyst is illustrated.
The catalyst is prepared by impregnating a CaCO ₃ support with the palladium precursor PdCl ₂ in a basic medium stirred in water and heated at 80 ° C. The mixture is then reduced by adding formaldehyde. The solution is stirred, filtered, washed and dried at 150 ° C. for 10 hours.
The hydrogenation reaction in the presence of this catalyst was carried out in an autoclave according to the procedure described above.
The reaction was carried out under the following reaction conditions.
Concentration of 1,4-butynediol in water: 20%
Catalyst weight: 0.13 g
Temperature: 50 ° C
H ₂ pressure: 350 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 98.2%
[0037]
Example 5
10 times recycle use or performance of 1% Pd / CaCO ₃ catalyst in hydrogenation of 1,4-butynediol to 1,4-butenediol This example shows 1,4-butynediol converted to 1,4-butenediol Illustrates the 10 recycle use or performance of a 1% Pd / CaCO ₃ catalyst in the hydrogenation of NO.
The reaction in the presence of this catalyst was carried out in an autoclave according to the procedure described above.
The reaction was carried out under the following reaction conditions.
Catalyst: 1% Pd / CaCO ₃
Catalyst weight: 1.0 g
Number of grams of 1,4-butynediol converted: 2191
Temperature: 50 ° C
H ₂ pressure: 350 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 98%
TON: 4 × 10 ³ h ⁻¹
[0038]
Example 6
Performance of 1% Pd / BaCO ₃ catalyst in the hydrogenation of 1,4-butynediol to 1,4-butenediol This example illustrates 1 in the hydrogenation of 1,4-butynediol to 1,4-butenediol The performance of% Pd / BaCO ₃ catalyst is illustrated.
The catalyst is prepared by impregnating BaCO ₃ support with the palladium precursor PdCl ₂ in a basic medium stirred in water and heated at 80 ° C. The mixture is then reduced by adding formaldehyde. The solution is stirred, filtered, washed and dried at 150 ° C. for 10 hours.
The reaction in the presence of this catalyst was carried out in an autoclave according to the procedure described above.
The reaction was carried out under the following reaction conditions.
Concentration of 1,4-butynediol in water: 10%
Catalyst weight: 0.065 g
Temperature: 50 ° C
H ₂ pressure: 350 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 100%
[0039]
Example 7
The reaction was performed under the following reaction conditions.
Catalyst: 1% Pd / BaCO ₃
Catalyst weight: 0.13 g
Concentration of 1,4-butynediol in water: 20%
Temperature: 50 ° C
H ₂ pressure: 350 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 100%
[0040]
Example 8
The reaction was performed under the following reaction conditions.
Catalyst: 1% Pd / BaCO ₃
Catalyst weight: 0.13 g
Concentration of 1,4-butynediol in water: 20%
Temperature: 50 ° C
H ₂ pressure: 500 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 100%
[0041]
Example 9
The reaction was performed under the following reaction conditions.
Catalyst: 1% Pd / BaCO ₃
Catalyst weight: 0.13 g
Concentration of 1,4-butynediol in water: 20%
Temperature: 80 ° C
H ₂ pressure: 350 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 95.2%
By-product: 4.8%
[0042]
Example 10
The reaction was performed under the following reaction conditions.
Catalyst: 1% Pd / BaCO ₃
Catalyst weight: 0.13 g
Concentration of 1,4-butynediol in water: 20%
Temperature: 80 ° C
H ₂ pressure: 500 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 94.5%
By-product: 5.5%
[0043]
Example 11
The reaction was performed under the following reaction conditions.
Catalyst: 1% Pd / BaCO ₃
Catalyst weight: 0.23 g
Concentration of 1,4-butynediol in water: 35%
Temperature: 50 ° C
H ₂ pressure: 350 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 100%
[0044]
Example 12
The reaction was performed under the following reaction conditions.
Catalyst: 1% Pd / BaCO ₃
Catalyst weight: 0.46 g
Concentration of 1,4-butynediol in water: 70%
Temperature: 50 ° C
H ₂ pressure: 350 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 82.1%
[0045]
Example 13
This example illustrates the use or performance of a 1% Pd / NH ₄ -ZSM5 catalyst in the hydrogenation of 1,4-butynediol to 1,4-butenediol.
The catalyst is prepared by impregnating NH ₄ —ZSM5 support with a palladium precursor in a basic medium stirred in water and heated at 80 ° C. The mixture is then reduced by adding formaldehyde. The solution is stirred, filtered, washed and dried at 150 ° C. for 10 hours.
The hydrogenation reaction in the presence of this catalyst was carried out in an autoclave according to the procedure described above.
The reaction was carried out under the following reaction conditions.
Concentration of 1,4-butynediol in water: 20%
Catalyst weight: 0.13 g
Temperature: 50 ° C
H ₂ pressure: 350 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 100%
[0046]
Example 14
This example illustrates the use or performance of a 10% Ni-1% Pd / CaCO ₃ catalyst in the hydrogenation of 1,4-butynediol to 1,4-butenediol.
The catalyst is prepared by impregnating a CaCO ₃ support with a palladium precursor in a basic medium stirred in water and heated at 80 ° C. The mixture is then reduced by adding formaldehyde. The solution is stirred, filtered, washed and dried at 150 ° C. for 10 hours. The nickel nitrate solution is then stirred with 1% Pd / CaCO ₃ catalyst in basic medium, filtered, dried and then reduced at 500 ° C. under a stream of hydrogen.
The reaction in the presence of this catalyst was carried out in an autoclave according to the procedure described above.
The reaction was carried out under the following reaction conditions.
Concentration of 1,4-butynediol in water: 20%
Catalyst weight: 0.13 g
Temperature: 50 ° C
H ₂ pressure: 350 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 100%
[0047]
Example 15
This example illustrates the use or performance of a 1% Pt / MgCO ₃ catalyst in the hydrogenation of 1,4-butynediol to 1,4-butenediol.
The catalyst is prepared by impregnating MgCO ₃ support with platinum precursor PtCl ₂ in basic medium stirred in water and heated at 80 ° C. The mixture is then reduced by adding formaldehyde. The solution is stirred, filtered, washed and dried at 150 ° C. for 10 hours.
The hydrogenation reaction in the presence of this catalyst was carried out in an autoclave according to the procedure described above.
The reaction was carried out under the following reaction conditions.
Concentration of 1,4-butynediol in water: 20%
Catalyst weight: 0.13 g
Temperature: 50 ° C
H ₂ pressure: 350 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 99.8%
[0048]
Example 16
This example illustrates the use or performance of a 1% Pt / CaCO ₃ catalyst in the hydrogenation of 1,4-butynediol to 1,4-butenediol.
The catalyst is prepared by impregnating a CaCO ₃ support with a platinum precursor PtCl ₂ in a basic medium stirred in water and heated at 80 ° C. The mixture is then reduced by adding formaldehyde. The solution is stirred, filtered, washed and dried at 150 ° C. for 10 hours.
The hydrogenation reaction in the presence of this catalyst was carried out in an autoclave according to the procedure described above.
The reaction was carried out under the following reaction conditions.
Concentration of 1,4-butynediol in water: 10%
Catalyst weight: 0.065 g
Temperature: 50 ° C
H ₂ pressure: 350 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 100%
[0049]
Example 17
The reaction was carried out under the following reaction conditions.
Catalyst: 1% Pt / CaCO ₃
Catalyst weight: 0.13 g
Concentration of 1,4-butynediol in water: 20%
Temperature: 50 ° C
H ₂ pressure: 350 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 100%
[0050]
Example 18
The reaction was carried out under the following reaction conditions.
Catalyst: 1% Pt / CaCO ₃
Catalyst weight: 0.13 g
Concentration of 1,4-butynediol in water: 20%
Temperature: 50 ° C
H ₂ pressure: 500 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 100%
[0051]
Example 19
The reaction was carried out under the following reaction conditions.
Catalyst: 1% Pt / CaCO ₃
Catalyst weight: 0.13 g
Concentration of 1,4-butynediol in water: 20%
Temperature: 80 ° C
H ₂ pressure: 350 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 97.2%
By-product: 2.8%
[0052]
Example 20
The reaction was carried out under the following reaction conditions.
Catalyst: 1% Pt / CaCO ₃
Catalyst weight: 0.13 g
Concentration of 1,4-butynediol in water: 20%
Temperature: 80 ° C
H ₂ pressure: 500 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 95.7%
By-product: 4.3%
[0053]
Example 21
The reaction was carried out under the following reaction conditions.
Catalyst: 1% Pt / CaCO ₃
Catalyst weight: 0.23 g
Concentration of 1,4-butynediol in water: 35%
Temperature: 50 ° C
H ₂ pressure: 350 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 100%
[0054]
Example 22
The reaction was carried out under the following reaction conditions.
Catalyst: 1% Pt / CaCO ₃
Catalyst weight: 0.46 g
Concentration of 1,4-butynediol in water: 70%
Temperature: 50 ° C
H ₂ pressure: 350 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 83.7%
[0055]
Example 23
This example illustrates the performance of a 1% Pt / BaCO ₃ catalyst in the hydrogenation of 1,4-butynediol to 1,4-butenediol.
The catalyst is prepared by impregnating BaCO ₃ support with platinum precursor PtCl ₂ in basic medium stirred in water and heated at 80 ° C. The mixture is then reduced by adding formaldehyde. The solution is stirred, filtered, washed and dried at 150 ° C. for 10 hours.
The reaction in the presence of this catalyst was carried out in an autoclave according to the procedure described above.
The reaction was carried out under the following reaction conditions.
Concentration of 1,4-butynediol in water: 20%
Catalyst weight: 0.13 g
Temperature: 50 ° C
H ₂ pressure: 350 psig
The following results are obtained:
Conversion rate of 1,4-butynediol: 100%
Selectivity to cis 1,4-butenediol: 99.9%
[0056]
Advantages of the invention 1. Selective hydrogenation of 1,4-butynediol to 1,4-butenediol includes novel 1% Pt / MgCO ₃ , 1% Pt / CaCO ₃ , 1% Pt / BaCO ₃ , Poisoned using 1% Pd / MgCO ₃ , 1% Pd / CaCO ₃ , 1% Pd / BaCO ₃ , 1% Pd / NH ₄ -ZSM-5 and 10% Ni-1% Pd / CaCO ₃ catalyst Done without.
2. With almost 100% selectivity to cis 1,4-butenediol, a substantially complete conversion of 1,4-butynediol to 1,4-butenediol was performed under relatively mild process conditions. Is called.
3. Separation of the product 1,4-butenediol in pure form is facilitated by removal of the catalyst from the reaction mixture.

Claims (7)

An aqueous solution of 1,4-butynediol is stirred under the following general formula AB (y) C (z) (wherein A is a carrier containing a Group IIA metal carbonate or zeolite, and B is Pd Or Pt, y is 0.2 to 10%, C is nickel, and z is 0 to 15.0%, provided that z is 0 when B is Pt). hydrogen to a temperature in the range of 20 to 110 ° C. in a basic medium and ^{200~700psig (1.38~4.83MPag (N.m -2 g)} ) reaction in the range of H ₂ pressure is completed at the upper A process for producing 1,4-butenediol, comprising cooling the reaction mixture to room temperature and separating the catalyst to obtain 1,4-butenediol by known methods.   The process according to claim 1, wherein the concentration of 1,4-butynediol in the aqueous medium is in the range of 10-50%. The process according to claim 1 or 2 , wherein the pH of the reaction mixture is maintained in the range of 8 to 10 by adding a base.   4. A process according to claim 3, wherein the base is ammonia. The method according to any one of claims 1 to 4 , wherein the temperature of the reaction is in the range of 30 to 90 ° C. The process according to any one of claims 1 to 5, wherein the catalyst is recycled 10 times without losing its activity and selectivity and the turnover value (TON) is 4 x 10 ³ h ^-1 . The method of any one of claims 1 to 6 , wherein the catalyst comprises palladium and nickel .